The present invention relates to a scanning method and apparatus for use in a disk player such as a compact disk (CD) player or video disk player.
Conventional disk players are capable of performing a scanning operation in which a track jump operation and track tracing operation by the information detecting point of the pickup are alternately performed. High-speed reproduction of recorded information can be achieved using such a scanning operation.
Conventionally, for performing such a scanning operation, there has been employed a method in which a slider servo for controlling the relative position, in the radial direction of a recorded disk, of a slider carrying the pickup is disabled and then the slider is forcibly moved. According to such a conventional method, when the amount of deviation of a tracking actuator incorporated in the pickup becomes large and reaches near the limit of its movable range, a protective circuit for opening the tracking servo loop so as to protect the tracking actuator is operated to cause the tracking actuator to return to the center of its movable range. The information detecting point is made to jump over tracks by the operation of the tracking actuator. Then, the tracking servo loop is closed until the protective circuit is actuated again after the jump operation, whereupon the information detecting point traces a track to thereby read out recorded information from the track.
In such a conventional scanning method, there has been a problem in that the speed of reproduction cannot be made constant since the speed of the slider varies depending on its relative position in the radial direction and the direction of jumping in accordance with the characteristics of the slider unit.